EASY MOBILITY: A set of four wheels let you move this base across multiple surfaces while two wheel locks help keep your shading in place STURDY ANCHOR: A heavy weighted base keeps your umbrella firmly in place-resisting the wind while supporting your shade; weight with sand: 136.70lbs/ weight with water: 94.47lbs REFILLABLE RESERVOIR: Fill the hollow chamber with 120 pounds of sand or 38 liters of water, then use a pair of tightening knobs to secure your umbrella USE IT ANYWHERE: Perfect for any patio, deck, or outdoor seating area, the wheels roll freely across wood or concrete and lock in place for long days in the shade FITS MARKET UMBRELLAS 6-12FT: A contemporary design blends with most outdoor decorations and fits most market umbrellas sized 6-12ft with poles sized 1.5-1.9in